Product information: RC100 (5V) Noiseless Resistor Cable

These small resistors convert 3-pin fans from 12 volts to approximately 7 volts (RC56) and 5 volts (RC100). This basically means it reduces the speed of your 3-pin fan, which in turn reduces the noise the fan makes. We tested the RC56 resistor with a 92mm fan and without the resistor installed the fan ran at 2700 RPM. Once the resistor was installed the fan ran around 1400 RPM. The reduction in noise was significant. The RC100 would reduce the speed of the fan to around 1100 RPM, making the fan even quieter!